A dispersion formed of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(styrenesulfonate) (PSS) is called PEDOT:PSS. The role of PSS is to maintain solubility and stability of PEDT in the solution. Also, PEDOT is able to polymerize under the presence of PSS. During polymerization, oxide is doped to form PEDOT:PSS, creating a charged polymer capable of conducting holes.
In a well-known LED structure, the mixture of PEDOT and PSS (PEDOT:PSS) is used as the material for a conductive transparent polymer layer. However, the transparency of PEDOT:PSS is not excellent, even to the extent of exhibiting dark blue chroma. It also lacks some mechanical properties such as wear resistance, so it has to be coated on hard substrate, usually ITO, which offers mechanical support. For current industries, applications of these prior-art techniques can no longer meet the demands of our daily life, especially, the demand for flexibility. Although transparent and flexible synthetic resins such as polyamide, poly(ethylene terephthalate), polycarbonate, polyethylene and polyvinyl chloride are currently used as flexible substrates, hard materials like ITO are mostly employed as the electrode substrates, which hinders the overall flexibility of the design. Moreover, as mentioned before, PEDOT:PSS itself has good conductivity, but lacks transparency and stability due to resistance drift. Thus, it cannot be used as a commercial replacement for ITO, but ITO has poor flexibility. Thus, there is still a need in the industry to provide a LED transparent flexible display structure that overcomes the shortcomings in the prior art.